Field of the Invention
The present invention relates to a controller for a wire electric discharge machine having a consumable exchange function.
Description of the Related Art
In a case where a wire electric discharge machine is incorporated in a mass-production machining line in a manufacturing factory, the machine is required to be continuously operated for a long period to improve productivity. In this case, a wire electric discharge machining system including a workpiece exchanging unit that automatically exchanges a workpiece is employed. However, when any of a variety of consumables of the wire electric discharge machine reaches the end of its life and is therefore required to be exchanged, it is necessary to temporarily stop the continuous operation of the machine, manually exchange the consumable, and resume the operation. The series of task obstruct the continuous automatic operation for a long period and therefore hinder improvement in productivity.
Technologies for detecting that a consumable of a wire electric discharge machine has reached the end of its life and detecting a remaining life of a consumable thereof have been proposed, as shown in the following patent literatures. The technologies are, however, directed to how to notify an operator that time for exchange of a consumable has come, for example, by displaying the notification on a display device to prompt the operator to exchange the consumable.
Japanese Patent Application Laid-Open No. 2010-179377 discloses a wire electric discharge machine that detects the amount of remaining wire based on detected wire tension, wherein the machine analyzes a machining program before a workpiece is machined to determine a wire length necessary for the machining, compares the determined wire length with the detected amount of remaining wire to evaluate whether or not a wire bobbin is required to be exchanged, and displays a result of the evaluation on a display device.
Japanese Patent Application Laid-Open No. 2003-25155 discloses a wire electric discharge machine that calculates the amount of remaining wire, analyzes a machining program to calculate the amount of wire to be consumed for each machining condition unit, and compares the amount of remaining wire with the amount of consumed wire to notify a point of time when the no wire is left or a point of time when a wire electrode should be exchanged.
Japanese Patent Application Laid-Open No. 5-42414 discloses a controller for a wire electric discharge machine, wherein the controller issues, when a turbidity or pH value of a machining liquid is smaller than a predetermined value, a warning that prompts an operator to exchange a filter.
Japanese Patent Application Laid-Open No. 5-305520 discloses a wire electric discharge machine that detects the degree of consumption of upper and lower power feeders (electrode pins) based on the impedance of each of the upper and lower power feeders and a preset value for evaluation.
Japanese Patent Application Laid-Open No. 2004-358573 discloses a machining liquid processing apparatus for a wire electric discharge machine, wherein the processing apparatus monitors ion exchange performance (specific resistance) of an ion exchange resin to estimate the life of the ion exchange resin and displays a result of the estimation on display means. The processing apparatus has a configuration in which an alarm is displayed in accordance with the life to prompt an operator to exchange the ion exchange resin.
Japanese Patent Application Laid-Open No. 9-216129 discloses an electric discharge machine including a workpiece handing robot that removes a workpiece and a core, wherein the workpiece handing robot is disposed in a position outside a machining tank.
Japanese Patent Application Laid-Open No. 8-118151 discloses a wire electric discharge machine that automatically exchanges a head having power feeders (electrode pins) and a wire guide, wherein durable hours of the power feeders are registered in advance and when hours of operation of the wire electric discharge machine become equal to the durable hours, machining operation is temporarily stopped and the head is exchanged.
Japanese Patent Application Laid-Open No. 7-266137 discloses a wire electric discharge machine having a workpiece exchanger including means for drying a machined workpiece and means for preventing the machined workpiece from rusting.